Blends of polyetherimide resins and polyester resins that form transparent articles are derived predominantly from alicylic hydrocarbon diol, and a carbocyclic di-carboxylic acid, such as poly ethylene terephthalate as disclosed in U.S. Pat. No. 4,141,927 (hereby incorporated by reference), while those disclosed in U.S. Pat. No. 5,439,987, which are derived predominantly from cyclohexanedimethanol and a carbocyclic dicarboxylic acid, such as, for example, a poly(cyclohexane-dimethanol terephthalate) resin, are said to provide improved impact strength. Blends of polyetherimide resins and copolyesters of terephthalic acid and/or isoterephthalic acid, 1,4-cyclohexanedimethanol and ethylene glycol, that is, certain poly(cyclohexane-1,4-dimethylene-co-ethylene terephthalate) resins that are said to exhibit a high flexural modulus are also disclosed in U.S. Pat. No. 5,439,987.
When these polyetherimide-polyester blends are utilized in molding large parts or making blends with other polymers, a color shift often results in increased rejection rates and other quality issues. Consequently, polyetherimide-polyester blends that exhibit color stability, resistance to elevated temperature and further improvements are desired.